restore: Gather setting agrument for sigreturn code in one place
restore: Gather setting agrument for sigreturn code in one place

Also add a few more comments.

Signed-off-by: Cyrill Gorcunov <7a1ea01eee6961eb1e372e3508c2670446d086f4@openvz.org>

LK4D4/criu,KKoukiou/criu-remote,gonkulator/criu,svloyso/criu,svloyso/criu,fbocharov/criu,rentzsch/criu,fbocharov/criu,sdgdsffdsfff/criu,tych0/criu,marcosnils/criu,gonkulator/criu,ldu4/criu,fbocharov/criu,AuthenticEshkinKot/criu,ldu4/criu,marcosnils/criu,ldu4/criu,rentzsch/criu,tych0/criu,gonkulator/criu,kawamuray/criu,LK4D4/criu,gablg1/criu,biddyweb/criu,efiop/criu,ldu4/criu,gablg1/criu,wtf42/criu,AuthenticEshkinKot/criu,efiop/criu,wtf42/criu,LK4D4/criu,marcosnils/criu,gonkulator/criu,KKoukiou/criu-remote,eabatalov/criu,eabatalov/criu,svloyso/criu,marcosnils/criu,biddyweb/criu,gablg1/criu,kawamuray/criu,AuthenticEshkinKot/criu,rentzsch/criu,sdgdsffdsfff/criu,AuthenticEshkinKot/criu,sdgdsffdsfff/criu,eabatalov/criu,wtf42/criu,kawamuray/criu,eabatalov/criu,gablg1/criu,svloyso/criu,ldu4/criu,biddyweb/criu,wtf42/criu,efiop/criu,KKoukiou/criu-remote,LK4D4/criu,biddyweb/criu,sdgdsffdsfff/criu,AuthenticEshkinKot/criu,AuthenticEshkinKot/criu,tych0/criu,eabatalov/criu,marcosnils/criu,efiop/criu,gablg1/criu,kawamuray/criu,fbocharov/criu,svloyso/criu,gablg1/criu,gonkulator/criu,sdgdsffdsfff/criu,biddyweb/criu,marcosnils/criu,tych0/criu,rentzsch/criu,rentzsch/criu,LK4D4/criu,biddyweb/criu,kawamuray/criu,ldu4/criu,rentzsch/criu,wtf42/criu,KKoukiou/criu-remote,LK4D4/criu,gonkulator/criu,KKoukiou/criu-remote,fbocharov/criu,KKoukiou/criu-remote,sdgdsffdsfff/criu,tych0/criu,fbocharov/criu,eabatalov/criu,efiop/criu,wtf42/criu,kawamuray/criu,svloyso/criu,tych0/criu,efiop/criu